This invention relates to micropipette pullers of the type shown in my earlier U.S. Pat. No. 4,600,424 granted July 15, 1986. Micropipette pullers generally employ a filament comprising a metal band or wire, which is bent into a ring to surround the glass tubing and then energized electrically to heat the tubing to its melting point. The heating capacity of such a filament is of course limited to the melting point of the metal from which the filament is formed and, therefore, in the aforesaid co-pending application, I introduced a laser device, which is not so limited, as the source of heat. However, in the apparatus there disclosed, the laser beam was directed against one side of the tubing, with the result that the opposite side of the tubing was not heated to the same extent. That is, the tubing was not heated uniformly around its circumferences.